JP2010282867A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably prevent deformation of metal separators to connecting-path sides, and to smoothly circulate fluid. <P>SOLUTION: A first metal separator 16 for composing a fuel cell stack includes: a plurality of connecting paths 28a for allowing an oxidant gas passage 26 to communicate with an oxidant gas inlet communicating hole 20a; and a plurality of connecting paths 28b for allowing the oxidant gas passage 26 to communicate with an oxidant gas outlet communicating hole 20b. The connecting paths 28a are formed among a plurality of rubber bridges 30a. By setting the shape of the rubber bridge 30a, the connecting path 28a includes a first path section 36a at the side of the oxidant gas passage 26, a second path section 38a at the side of the oxidant gas inlet communicating hole 20a, and an intermediate path section 40a between the first and second path sections 36a, 38a. Dimensions of opening width of the intermediate path section 40a are set to be smaller than those of the first and second path sections 36a, 38a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, an electrolyte / electrode structure having a pair of electrodes disposed on both sides of an electrolyte and a metal separator are laminated, and at least a fluid that is any one of a fuel gas, an oxidant gas, and a cooling medium is supplied to the metal separator. The present invention relates to a fuel cell stack in which a fluid flow path that flows in the direction of the surface and fluid communication holes that supply the fluid in the stacking direction are formed.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is provided by a pair of separators. The unit cell is sandwiched. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of unit cells.

  In the fuel cell described above, a fuel gas flow path (fluid flow path) for flowing a fuel gas (fluid) facing the anode side electrode and an oxidant gas (face) facing the cathode side electrode in the plane of the separator. And an oxidant gas flow path (fluid flow path) for flowing a fluid. Further, a fuel gas inlet communication hole and a fuel gas outlet communication hole that are fluid communication holes that penetrate the separator in the stacking direction and communicate with the fuel gas flow path, and an oxidant gas flow path An oxidant gas inlet communication hole and an oxidant gas outlet communication hole, which are fluid communication holes communicating with each other, are formed. In addition, a cooling medium flow path (fluid flow path) for cooling the electrolyte membrane / electrode structure is provided between the separators, and a cooling medium inlet communication that penetrates in the stacking direction and communicates with the cooling medium flow path. A hole and a cooling medium outlet communication hole (fluid communication hole) are formed.

  In this case, the fluid flow path and the fluid communication hole communicate with each other via a connection flow path having a plurality of grooves and the like in order to allow fluid to flow smoothly and evenly. For example, the fuel cell disclosed in Patent Document 1 includes a seal member 1 as shown in FIG. 10, and a porous body flow functioning as a flow path for an oxidant gas is provided on the seal member 1. A path 2 is provided.

  On both sides of the seal member 1, an oxidant gas supply manifold 3 and an oxidant gas discharge manifold 4 that are elongated in the vertical direction are formed opposite to each other. Between the oxidant gas supply manifold 3 and the oxidant gas discharge manifold 4 and the porous body flow path 2, oxidant gas flow paths 5a and 5b are alternately formed.

  The oxidant gas flow path 5a is formed so that the cross-sectional area gradually decreases outward from the porous body flow path 2 side, while the oxidant gas flow path 5b is formed from the porous body flow path 2 side. The cross-sectional area is gradually increased toward the outside.

  Accordingly, in the oxidant gas flow path 5a, water generated by power generation is sucked to the manifold side by capillary action, while the oxidant gas flow path 5b remains in the oxidant gas flow path 5b when power generation is stopped. It is assumed that the water that is present can be sucked into the porous channel 2 side.

JP 2008-53105 A

  In the above-mentioned Patent Document 1, the groove portion is formed in the seal member 1 to form the oxidant gas flow paths 5a and 5b each having a triangular shape in plan view, and a metal separator (not shown) is formed in the seal member 1. Are stacked. At that time, the metal separator only comes into contact with the narrow partition surface between the oxidant gas flow paths 5a and 5b, and the contact area is reduced, and the deformation amount of the metal separator may be increased. Thereby, there exists a problem that a seal linear pressure falls.

  Moreover, the generated water may be continuously sucked from the porous body flow path 2 to the oxidant gas discharge manifold 4 by the oxidant gas flow path 5a. Thereby, there exists a problem that a ground fault generate | occur | produces between each cell through the continuous produced | generated water.

  The present invention solves this type of problem, and provides a fuel cell stack that can satisfactorily suppress deformation of a metal separator toward the connecting passage and can smoothly flow fluid. Objective.

  In the present invention, an electrolyte / electrode structure having a pair of electrodes disposed on both sides of an electrolyte and a metal separator are laminated, and at least a fluid that is any one of a fuel gas, an oxidant gas, and a cooling medium is supplied to the metal separator. The present invention relates to a fuel cell stack in which a fluid flow path that flows in the surface direction and a fluid communication hole that supplies the fluid in the stacking direction are formed.

  The metal separator is provided with a plurality of connecting passages that communicate between the fluid flow path and the fluid communication hole, and the connection passage includes a first passage portion on the fluid flow path side and a second passage on the fluid communication hole side. A passage portion and an intermediate passage portion between the first passage portion and the second passage portion, and the intermediate passage portion is set to have a smaller opening width than the first passage portion and the second passage portion; Has been.

  Moreover, it is preferable that the both wall surfaces which form an intermediate channel part are set mutually parallel along the flow direction of a fluid.

  Furthermore, it is preferable that a 1st channel | path part and a 2nd channel | path part are formed by the wall surface of a phase shape.

  Furthermore, it is preferable that the second passage portion is wider than the first passage portion.

  According to the present invention, the connecting passage that communicates between the fluid flow path and the fluid communication hole is provided with an intermediate passage portion having a small opening width at the center, so that the adjacent metal separator is transformed into a connecting passage. It can suppress well. Therefore, the fuel cell does not cause a decrease in power generation performance due to load loss.

  In addition, on both sides of the intermediate passage portion, the first passage portion and the second passage portion having a larger opening width than the intermediate passage portion are provided. For this reason, for example, the pressure loss of the reaction gas from the first passage portion toward the intermediate passage portion is increased, and the generated water can be discharged well into the fluid communication hole. Thereby, supply failure of the reaction gas due to the blockage of the flow path can be prevented, and desired power generation performance can be ensured.

It is a principal part disassembled perspective explanatory drawing of the fuel cell stack which concerns on the 1st Embodiment of this invention. FIG. 2 is a sectional view of the fuel cell stack taken along line II-II in FIG. 1. It is front explanatory drawing of the 1st metal separator which comprises the said fuel cell stack. It is principal part perspective explanatory drawing of the said 1st metal separator. It is explanatory drawing of one surface of the 2nd metal separator which comprises the said fuel cell stack. It is explanatory drawing of the other surface of the said 2nd metal separator. It is explanatory drawing of one surface of the 1st metal separator which comprises the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is principal part perspective explanatory drawing of the said 1st metal separator. It is explanatory drawing of another connection channel | path. It is front view explanatory drawing of the sealing member which comprises the fuel cell which concerns on patent document 1. FIG.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the first embodiment of the present invention has a plurality of fuel cells 12 stacked in the horizontal direction (arrow A direction) or the vertical direction (arrow C direction). .

  In the fuel cell 12, an electrolyte membrane / electrode structure (electrolyte / electrode structure) 14 is sandwiched between first and second metal separators 16 and 18. The first and second metal separators 16 and 18 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or the like.

  As shown in FIG. 1, one end edge of the fuel cell 12 in the arrow B direction (horizontal direction in FIG. 1) communicates with each other in the arrow A direction, which is the stacking direction, and contains an oxidant gas, for example, oxygen An oxidant gas inlet communication hole 20a for supplying gas, a cooling medium inlet communication hole 22a for supplying a cooling medium, and a fuel gas outlet communication hole 24b for discharging a fuel gas, for example, a hydrogen-containing gas, Arranged in the direction of arrow C (vertical direction).

  The other end edge of the fuel cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, the fuel gas inlet communication hole 24a for supplying fuel gas, and the cooling medium outlet communication hole for discharging the cooling medium. 22b and an oxidant gas outlet communication hole 20b for discharging the oxidant gas are arranged in the direction of arrow C.

  As shown in FIGS. 1 and 3, an oxidant gas channel (fluid channel) 26 extending in the direction of arrow B is provided on the surface 16a of the first metal separator 16 on the electrolyte membrane / electrode structure 14 side. It is done. The oxidant gas flow path 26 includes a plurality of grooves provided by forming the first metal separator 16 into a wave shape, and the oxidant gas flow path 26, the oxidant gas inlet communication hole 20a, and the oxidant gas. The outlet communication hole 20b communicates with the connection passages 28a and 28b.

  The connecting passage 28a is formed by a plurality of rubber bridges 30a arranged in the direction of arrow C. As shown in FIGS. 3 and 4, each rubber bridge 30 a has a circular columnar portion 32 a having a circular shape in plan view, and a pair of rectangular column portions 34 a that bulges from the intermediate portion in the arrow B direction to the both ends in the arrow C direction. And are integrally molded.

  A connecting passage 28a is formed between the rubber bridges 30a. The connection passage 28a includes a first passage portion 36a on the oxidant gas flow channel 26 side, a second passage portion 38a on the oxidant gas inlet communication hole 20a side, and the first passage portion 36a and the second passage portion 38a. There is an intermediate passage portion 40a therebetween.

  The intermediate passage portion 40a is set to have a smaller opening width than the first passage portion 36a and the second passage portion 38a. Specifically, the intermediate passage portion 40a is formed between the wall surfaces of the prism portions 34a facing each other of each rubber bridge 30a, and the wall surfaces are set parallel to each other along the flow direction of the oxidant gas. . The 1st channel | path part 36a and the 2nd channel | path part 38a are formed of the curved-shaped wall surface of the cylindrical part 32a, and are expanded in the direction which mutually spaces apart.

  The connecting passage 28b is formed between the plurality of rubber bridges 30b. The same reference numerals are given to the same components as the connecting passage 28a, and the detailed description thereof is omitted (see FIG. 3). .

  The first seal member (rubber seal member) 42 is integrated with the surfaces 16a and 16b of the first metal separator 16 by baking or injection molding around the outer peripheral end portion of the first metal separator 16. . The first seal member 42 uses, for example, a seal material such as EPDM, NBR, fluorine rubber, silicon rubber, fluorosilicon rubber, butyl rubber, natural rubber, styrene rubber, chloroplane, or acrylic rubber, a cushion material, or a packing material. To do. The rubber bridges 30a and 30b are configured integrally with the first seal member 42 or separately.

  As shown in FIGS. 1 and 5, the surface 18a of the second metal separator 18 on the electrolyte membrane / electrode structure 14 side communicates with the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b. A fuel gas channel (fluid channel) 44 extending in the direction is formed. The fuel gas flow path 44 includes a plurality of grooves, and the fuel gas flow path 44 communicates with the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b via connection passages 46a and 46b.

  The connecting passages 46a and 46b are formed by a plurality of rubber bridges 48a and 48b. The rubber bridges 48a and 48b are configured similarly to the rubber bridges 30a and 30b described above, and will be briefly described below.

  The connection passage 46a includes a first passage portion 50a on the fuel gas passage 44 side, a second passage portion 52a on the fuel gas inlet communication hole 24a side, and a space between the first passage portion 50a and the second passage portion 52a. An intermediate passage portion 54a is provided. The intermediate passage portion 54a is set to have a smaller opening width than the first passage portion 50a and the second passage portion 52a.

  The connection passage 46b includes a first passage portion 50b on the fuel gas passage 44 side, a second passage portion 52b on the fuel gas outlet communication hole 24b side, and a space between the first passage portion 50b and the second passage portion 52b. An intermediate passage portion 54b is provided. The intermediate passage portion 54b is set to have a smaller opening width than the first passage portion 50b and the second passage portion 52b.

  A second seal member (rubber seal member) 56 is integrated with the surfaces 18 a and 18 b of the second metal separator 18 around the outer peripheral end of the second metal separator 18. The second seal member 56 is made of the same material as the first seal member 42 of the first metal separator 16.

  As shown in FIG. 1, a cooling medium flow path (fluid flow path) communicating with the cooling medium inlet communication hole 22 a and the cooling medium outlet communication hole 22 b is provided on a surface 18 b opposite to the surface 18 a of the second metal separator 18. 58 is formed. Connection passages 60a and 60b are formed in the vicinity of the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b.

  The connecting passages 60a and 60b are formed by a plurality of rubber bridges 62a and 62b, respectively. As shown in FIG. 6, the connecting passage 60a includes a first passage portion 64a on the cooling medium flow path 58 side, a second passage portion 66a on the cooling medium inlet communication hole 22a side, and the first passage portion 64a and the second passage. There is an intermediate passage portion 68a between the passage portion 66a. The intermediate passage portion 68a is set to have a smaller opening width than the first passage portion 64a and the second passage portion 66a.

  Similarly, the connecting passage 60b includes a first passage portion 64b on the cooling medium passage 58 side, a second passage portion 66b on the cooling medium outlet communication hole 22b side, and the first passage portion 64b and the second passage portion 66b. Intermediate passage portion 68b between the two. The intermediate passage portion 68b is set to have a smaller opening width than the first passage portion 64b and the second passage portion 66b.

  As shown in FIG. 1, the electrolyte membrane / electrode structure 14 includes, for example, a solid polymer electrolyte membrane 70 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side sandwiching the solid polymer electrolyte membrane 70. The electrode 72 and the cathode side electrode 74 are provided.

  The anode side electrode 72 and the cathode side electrode 74 include a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. And have. The electrode catalyst layers are bonded to both surfaces of the solid polymer electrolyte membrane 70 so as to face each other with the solid polymer electrolyte membrane 70 interposed therebetween.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 1, a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a, and an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 20a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 22a.

  Therefore, as shown in FIG. 5, the fuel gas is introduced into the fuel gas flow path 44 after passing through the connection passage 46 a from the fuel gas inlet communication hole 24 a of the second metal separator 18. In the fuel gas channel 44, the fuel gas is supplied to the anode side electrode 72 constituting the electrolyte membrane / electrode structure 14 while moving in the arrow B direction.

  On the other hand, as shown in FIGS. 2 to 4, the oxidant gas is introduced from the oxidant gas inlet communication hole 20 a to the first metal separator 16 through the connection passage 28 a and into the oxidant gas flow path 26. As a result, the oxidant gas is supplied to the cathode side electrode 74 constituting the electrolyte membrane / electrode structure 14 while moving in the direction of arrow B in the oxidant gas flow path 26.

  Therefore, in the electrolyte membrane / electrode structure 14, the oxidant gas supplied to the cathode side electrode 74 and the fuel gas supplied to the anode side electrode 72 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the fuel gas consumed by being supplied to the anode side electrode 72 is discharged to the fuel gas outlet communication hole 24b through the connection passage 46b (see FIG. 5). Similarly, the oxidant gas supplied to the cathode side electrode 74 and consumed is discharged to the oxidant gas outlet communication hole 20b through the connection passage 28b (see FIG. 3).

  Further, the cooling medium supplied to the cooling medium inlet communication hole 22a is introduced into the cooling medium flow path 58 between the first and second metal separators 16 and 18 through the connection passage 60a as shown in FIG. Then, it circulates in the direction of arrow B. The cooling medium cools the electrolyte membrane / electrode structure 14 and then is discharged to the cooling medium outlet communication hole 22b through the connection passage 60b.

  In this case, in the first embodiment, as shown in FIGS. 3 and 4, the connecting passage 28a is interposed between the oxidizing gas inlet communication hole 20a and the oxidizing gas passage 26 via a plurality of rubber bridges 30a. Is formed.

  The connecting passage 28a is provided with an intermediate passage portion 40a having a small opening width at the center by setting the rubber bridge 30a to a shape having a cylindrical portion 32a and a prism portion 34a. For this reason, it is possible to suppress the deformation of the second metal separator 18 adjacent to the first metal separator 16 in the intermediate passage portion 40a formed between the rubber bridges 30a. It becomes possible to prevent omission. As a result, the fuel cell 12 does not cause a decrease in power generation performance due to load loss.

  In addition, on both sides of the intermediate passage portion 40a, a first passage portion 36a and a second passage portion 38a having a larger opening width than the intermediate passage portion 40a are provided. Therefore, the flow rate of the oxidant gas supplied from the oxidant gas inlet communication hole 20a to the oxidant gas flow path 26 is prevented, and the pressure loss of the oxidant gas is increased by the throttle function of the intermediate passage part 40a. For this reason, it is possible to remove moisture uniformly by spraying the oxidant gas flow path 26 and to improve the supply of the oxidant gas.

  Further, the connecting passage 28a has a first passage portion 36a and a second passage portion 38a that expand on both sides with the intermediate passage portion 40a interposed therebetween. Thereby, dew condensation water does not continue along the connection passage 28a, and it becomes possible to prevent the occurrence of a ground fault in the fuel cell 12 as much as possible.

  Furthermore, each rubber bridge 30a has a cylindrical portion 32a, and a first passage portion 36a and a second passage portion 38a are formed along the curved wall surface of the cylindrical portion 32a. Therefore, the oxidant gas can smoothly and reliably flow along the curved surface shape from the oxidant gas inlet communication hole 20a to the oxidant gas flow path 26.

  Further, the intermediate passage portion 40a is configured in parallel with the flow direction of the oxidant gas by the parallel wall surfaces of the respective prism portions 34a. Therefore, the adjacent second metal separator 18 can be received by the parallel end surfaces of the prismatic portions 34a and 34b, and the deformation amount of the second metal separator 18 does not fluctuate, and a desired seal linear pressure can be obtained. Can be secured.

  On the other hand, a connecting passage 28b is formed between the oxidizing gas channel 26 and the oxidizing gas outlet communication hole 20b. In this connection passage 28b, in particular, the generated water present in the oxidant gas flow path 26 can be discharged well and reliably into the oxidant gas outlet communication hole 20b under the throttling action of the intermediate passage portion 40b. Thereby, supply failure of the oxidant gas due to the blockage of the oxidant gas flow path 26 can be prevented, and desired power generation performance can be ensured.

  That is, in the first passage portion 36b, since the opening width dimension becomes narrower toward the intermediate passage portion 40b, the pressure loss is increased, and the flow rate of the oxidant gas is increased and the generated water can be discharged.

  Next, since the opening width dimension of the second passage portion 38b is expanded toward the oxidant gas outlet communication hole 20b, the pressure loss is reduced, the flow velocity is reduced, and the discharge of the generated water becomes intermittent. Therefore, the generated water does not continue and it is possible to prevent a ground fault.

  Furthermore, in the fuel gas flow path 44, a connection passage 46a is provided in the vicinity of the fuel gas inlet communication hole 24a, and a connection passage 46b is provided in the vicinity of the fuel gas outlet communication hole 24b. The same effect as that of the agent gas channel 26 is obtained.

  In the cooling medium channel 58, connection passages 60a and 60b are formed in the vicinity of the cooling medium inlet communication hole 22a and in the vicinity of the cooling medium outlet communication hole 22b, respectively. For this reason, while suppressing the deformation | transformation of the 1st metal separator 16, the same effect is acquired, such as being able to ensure the flow volume of a cooling medium.

  FIG. 7 is an explanatory view of one surface 16a of the first metal separator 80 constituting the fuel cell stack according to the second embodiment of the present invention. In addition, the same referential mark is attached | subjected to the component same as the 1st metal separator 16 which comprises the fuel cell 12 which concerns on 1st Embodiment, and the detailed description is abbreviate | omitted.

  The first metal separator 80 is provided in the vicinity of the oxidant gas inlet communication hole 20a and the oxidant gas outlet communication hole 20b and is provided with connection passages 82a and 82b. The connecting passages 82a and 82b are formed between the plurality of rubber bridges 84a and 84b.

  As shown in FIG. 8, the rubber bridge 84a has a substantially octagonal shape when viewed from the front by forming a flat portion 86 by notching the corner portion of the center side in the arrow B direction of the generally hexagonal shape when viewed from the front.

  The connecting passage 82a is formed between the rubber bridges 84a, and includes a first passage portion 88a on the oxidant gas passage 26 side, a second passage portion 90a on the oxidant gas inlet communication hole 20a side, and the first passage portion 88a. And an intermediate passage portion 92a between the second passage portion 90a.

  The intermediate passage portion 92a is set to have a smaller opening width than the first passage portion 88a and the second passage portion 90a. Specifically, the intermediate passage portion 92a is formed between the flat portions 86 of the adjacent rubber bridges 84a in parallel with the arrow B direction, and the first passage portion 88a and the second passage portion 90a are formed of the rubber bridge. 84a is formed between the inclined wall surfaces.

  The connection passage 82b is configured in the same manner as the connection passage 82a described above, and the same reference numerals are given to the same components, and detailed description thereof is omitted. Further, although not shown, the second metal plate is similarly provided with a connecting passage.

  In the second embodiment configured as described above, the connecting passages 82a and 82b are provided with intermediate passage portions 92a and 92b having a small opening width at the center portion, and therefore the adjacent second metal separator is connected to the connecting passage 82a. , 82b can be prevented from being deformed. In addition, the first passage portions 88a and 88b and the second passage portions 90a and 90b having a larger opening width are provided on both sides of the intermediate passage portions 92a and 92b.

  Thereby, in 2nd Embodiment, while suppressing the fall of the power generation performance by load omission of a fuel cell, blocking | blocking of a flow path is prevented as much as possible, and generation | occurrence | production of a ground fault is prevented, and favorable power generation performance The same effects as those of the first embodiment can be obtained.

  In the second embodiment, the first passage portions 88a and 88b and the second passage portions 90a and 90b are expanded at the same inclination angle in the direction away from each other. However, the present invention is not limited to this. It is not something.

  For example, as shown in FIG. 9, the second passage portion 90b on the outlet side may be configured to expand at a larger angle than the first passage portion 88b. For this reason, especially the pressure loss of the 2nd channel | path part 90b becomes small, and the flow velocity of oxidizing agent gas becomes slow. Therefore, the generated water discharged from the oxidant gas flow channel 26 to the oxidant gas outlet communication hole 20b through the connection passage 82b is more reliably intermittently discharged, and a ground fault is generated due to the continuation of the generated water. It becomes possible to prevent it reliably.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Fuel cell 14 ... Electrolyte membrane electrode assembly 16, 18, 80 ... Metal separator 20a ... Oxidant gas inlet communication hole 20b ... Oxidant gas outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication hole 24a ... Fuel gas inlet communication hole 24b ... Fuel gas outlet communication hole 26 ... Oxidant gas flow path 28a, 28b, 46a, 46b, 60a, 60b, 82a, 82b ... Connection passages 30a, 30b, 48a, 48b, 62a, 62b, 84a, 84b ... Rubber bridge 32a ... Cylindrical part 34a, 34b ... Square column part 36a, 36b, 38a, 38b, 50a, 50b, 52a, 52b, 64a, 64b, 66a, 66b, 88a, 88b, 90a, 90b ... passage portions 40a, 40b, 54a, 54b, 68a, 68b, 92a, 92b ... intermediate passage Part 44: fuel gas flow path 58 ... coolant flow 70 ... solid polymer electrolyte membrane 72 ... anode 74 ... cathode 86 ... flat portion

Claims (4)

An electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of the electrolyte and a metal separator are laminated, and at least a fluid that is any one of a fuel gas, an oxidant gas, or a cooling medium is disposed in the surface direction of the metal separator. A fuel cell stack in which a fluid flow path for flowing and a fluid communication hole for supplying the fluid in the stacking direction are formed,
The metal separator is provided with a plurality of connection passages communicating between the fluid flow path and the fluid communication hole,
The connection passage has a first passage portion on the fluid flow path side, a second passage portion on the fluid communication hole side, and an intermediate passage portion between the first passage portion and the second passage portion,
The fuel cell stack, wherein the intermediate passage portion is set to have a smaller opening width than the first passage portion and the second passage portion.   2. The fuel cell stack according to claim 1, wherein both wall surfaces forming the intermediate passage are set in parallel to each other along the fluid flow direction.   3. The fuel cell stack according to claim 1, wherein the first passage portion and the second passage portion are formed by wall surfaces having a phase shape. 4.   4. The fuel cell stack according to claim 1, wherein the second passage portion is wider than the first passage portion. 5.

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